Magnetic separator for removing finely divided magnetic material from liquids



Nov. 4, 1947- w. BYRD, JR 2,430,157

MAGNETIC SEPARATOR FOR REMOVING ELY DIVIDED MAGNETIC MAT AL F L IDSFiled July 193 2 Sheets-Sheet 1 INVENTOR W/u/AM ByRaJQ.

- ATTORNEY 1947- w. BYRD, JR 2,430,157

MAGNEPIC SEPARATOR FOR REMOVING FINELY DIVIDED MAGNETIC MATERIAL FROMLIQUIDS Filed July ?9, 1939 2 Sheets-Sheet 2 I a 20 29 I u. 27 gi 7 c 2526 25 M8 T 26 INVENTOR 4 Patented Nov. 1947 MAGNETIC SEPARA'IOR FORREMOVIINE FINELY DIVIDED MAGNETIC MATER FROM LIQUIDS William Byrd, Jr.,Princeton, N. J. Application July 29, 1939, Serial No. 287,211

11 Claims. (Cl. 210-15) This invention relates to a magnetic separatorand particularly to a separator for removing finely divided magneticmaterial from liquids, sludges and the like.

An object of the invention is to provide an emcient separator of compactand inexpensive construction. Another object is to provide a separatorwhich may be easily and quickly cleaned when it-has become clogged andwhich may contain a replacement part of the simplest and cheapest type:

Separation of particles magnetically from a liquid, sludge, or slurry inwhich they are suspended is usually accomplished by passing the liquidcontaining the particles through a container or conduit in which arearranged grids of magnetizable material and subjecting the grids to theinfluence of a magnetic field. The magnetic field converges to anddiverges from the edges of the grids and since magnetic particles tendto travel from regions of less field density to regions of greater fielddensity, the particles migrate toward and are held on the edges of thegrids. Such grids are open to many objections, not the least among whichis that .they must be especially designed and manufactured to suit thepurpose and to fit the separator in which they are employed; thereforeboth original and replacement costs are high,

It has been suggested in the past that a mass of steel wool or chipsmight be substituted in place of an array of magnetizable grids, butthey have been found to be unsatisfactory for several reasons.

My invention contemplates the use, in place of an array of grids, of amaterial which, though so far as I am aware it has never been employedfor this purpose, is ideally suited therefor. It consists of a mass ofsmall, discrete'objects of like size and shape, each of which has one ormore sharp points and edges for collecting the smallest particles, and asubstantial body portion for conducting the magnetic flux. Cut tacks, orso called carpet tacks provide a splendid example of such objects. Whenplaced in a container they arrange themselves naturally and freely intoa mass in which the individual tacks lie in random orientations, withoutthe necessity of any pressing or shaking down. Their enlarged headsserve to maintain a spacing between adjacent tacks such that in the massthe iron occupies one third to o'ne half of the total volume and thevoids one half to two thirds. This arrangement provides the necessarylow reluctance path for the mag-- netic flux and at the same time leavesa multiplicity of tortuous paths through the mass whose cross'sectionsare great enough to permit the passage of the liquid or sludge withoutoffering excessive resistance to its flow. They have sharp thin pointsand sharp edges at which the mag-- netic fields are very dense anddivergent even when the magnetomotive force is relatively small. Theedges on their heads lie in planes perpendicular to the edges of theshanks, so that whatever the orientation in which a particular tack maylie, edges are presented to the magnetic flux. Furthermore, they are auniversal and inexpensive article of commerce.

A further advantage in the use of a mass of this character lies in thefact that the mass is substantially isotropic, in the sense that astackoi grids cannot be. Both the magnetic properties and liquidcapacity of the mass are the same in all directions. By its use,therefore, there is no difficulty in providing for liquid flow in anydesired direction relative to thedlrection of the magnetic field, whichis often difiicult in the case of grids.

I have found by numerous tests that substantially all of the finemagnetic particles suspended in a liquid are removed by passing theliquid through a separator containing such a mass of tacks.

My invention also contemplates the use of a removable tack-containingcartridge, which may be inserted in the separator with ease and mayeasily be removed and replaced. Whether in a cartridge or loose in theseparator, the tacks are easily and simply washed after they have beenremoved from the magnetic field and may be reused.

More particularly, the-invention consists in the novel construction andcombination of parts hereinafter described, illustrated in theaccompanying drawings and defined in the claims hereto appended, itbeing understood that various changes in form, proportion, size andminor details of construction within the scope of the claims may beresorted to without departing from the spirit or sacrificing any of theadvantages of the invention.

For a clearer comprehension of the invention reference is directed tothe. accompanying drawings which illustrate a preferred embodimentthereof, wherein:

Fig. 1 shows, in cross section, a magnetic separator in which themagnetic flux is derived from permanent magnets;

Fig. 2 shows a modification of a part of Fig. 1 including a removablecontainer or cartridge;

Fig,v 3 shows, in cross section, a separator in whi the magnetic flux isderived from a coil carrying an electric current;

,Fig. 4 shows a diiferent form of permanent magnet separator in whichadvantage is taken of certain of the subsidiary features of theinvention.

Referring now to Fig. 1, a cylindrical container l is provided at eitherend with hollow caps 2. The caps are externally threaded at 3 to fit theends 4 ofthe container and internally threaded at 5 to fit pipes forcarrying the liquid to and from the separator, Inside each cap 2 is aperforated metal plate or screen 6. The space defined by the cylindricalwalls of the container I and the plates flux when properly designed, andform with the container I a compact symmetrical structure.

The ends 4 of the container should be of magnetizable material such asiron, and are preferably of rectangular outside dimensions and ground ontwo opposite sides to provide smooth, low-reluctance joints with thepoles of the magnets Ill. The ends 4 may conveniently be fastened to thecylinder I by brazing. The caps 2 and perforated plates 6 are likewisepreferably of magnetizable material, though when the apparatus has theform shown this is not essential because the fiux may pass directly fromthe magnets Ill, through the magnetizable ends 4 of the container intothe mass of tacks I. However, the walls of the cylinder I should be ofnonmagnetic material, otherwise the flux would pass from pole to pole ofthe magnets through the walls instead of through the mass of tacks.

For cleaning, either of the screw caps 2 is removed and the container Iemptied and refilled with clean tacks.

Fig. 2 shows a modification in which one of the end caps 2' has aninterior threaded portion II of reduced diameter which engageswiththreads on a perforated cover I2 of a cylindrical container or cartridgeI3. The cartridge I3 is filled with tacks I and its other end I4. isperforated to allow passage of the liquid. It may be of light sheetmetal since great demands will not be made upon its strength. The crosssection of its walls may therefore be exceedingly low, and they may beof magnetic material without ill effects. It will be evident that whenthe The tacks l are placed in the annular space 25 below the permanentmagnet 20; and the casting 2| together with a plate 26 and disc 22provide a return path for the magnetic fiux. Thetacks 'I are preferablyplaced in a cartridge 21, having perforated walls, which may be screwedto the plate 26 as shown. The central tube 23 passes from top to bottomof the casting 2| and is provided with openings 28 through its walls atthe level of the annular space 25. The liquid is delivered through anopening 29 in the side of the casting 2! into an outer annular space 30and makes its Way to the outer periphery of the cartridge 21 and themass of tacks, passes radially through the mass and into the centraltube 23 through the openings 28 and out of the separator at the top ofthe tube 23. This construction with its short magnetic path through themass of tacks and its heavy yoke, provides a high magnetic fieldstrength among the tacks, while at the same time a large cross sectionis presented to the fiow of liquid, particularly at the outer radius ofthe annular mass of tacks.

It is of particular advantage to provide a large cross section where theliquid first enters the attracting mass, since it is there that magneticparticles are first caught and there that clogging tends to take place.With this radial construction clogging of the inner tacks takes placeonly by reason of magneticparticles which have not been caught by theouter tacks,

Below the casting 2| is a sealing plate 3| which may be of any material,provided at its inner face with a gasket 32. The whole apparatus may endcap 2 is unscrewed from the body of the cylinder I and withdrawn, thecartridge I3 containing the tacks and all the magnetic material caughtthereon is removed therewith. A fresh cartridge I3 may then be afiixedto the cap 2' and the cap and cartridge together be inserted in thecylinder I.

Fig. 3 shows a modification in which the magnetic field is provided by acoil l5 surrounding the cylinder l and carrying an electric current. Thecylinder, caps and perforated plates may be identical with those ofFig. 1. The ends I6 are modified to receive a yoke II, I8 of magneticmaterial placed outside the coil IE to provide a low reluctance returnpath for the magnetic flux. This yoke is made in two parts as shown topermitinstallation of the coil. From the separating standpoint theoperation of Fig. 3 is identiconveniently be held together inliquid-tight fashion by drawing up a cap 33 threaded to the lower end ofthe central tube 23 and provided with a gasket 34. With the constructionof Fig. 4, the tacks, whether in a cartridge or not, may be removed andreplaced without undoing the pipe connections.

Though I have described my invention in terms of a separator forremoving magnetic particles from liquids, it will be apparent that itwill be useful in other applications; for example, when it is desired toremove magnetic particles carried by other fluids such as air.

I claim:

1. A magnetic separator comprising a container, means for passing afluid bearing magnetic particles through said container, a mass ofsharpshanked, sharp-headed magnetizable tacks in said cal with that ofFig. 1; and moreoverFig. 3 may be modified by the addition of theremovable cartridge I3 of Fig. 2.

Fig. 4 shows a modification in which the direction of passage of themagnetic flux through the mass of tacks is perpendicular to thedirection of liquid fiow. A ring-shaped permanent magnet 20, magnetizedin the direction of its axis is held within a hollow casting 2I ofmagnetic material by amagnetic disc 22 threaded to a nonmagnetic centraltube 23 which in turn is screwed to the casting 2| and held fast by alocknut 24.

container and a source of magnetic flux, said 3. A magnetic separatorcomprising a, container, connections for passing a fluid bearingmagnetic particles through said container, a mass of like discretemagnetizable bodies disposed in random orientation in said container,each of said bodies having a sharp point, a sharp edged shank and anenlarged portion having a substantially sharp edge disposed in a planetransverse to the shank, and a source of magnetic flux, said mass andsaid source being so arranged that the mass forms a part of the magneticcircuit of the source.

4. A magnetic separator comprising a container, connections for passinga fluid bearing magnetic particles through said container, a mass oflike discrete magnetizable imperforate bodies in said container, each ofsaid bodies having a portion including an edge extended in a plane andanother portion including another edge extended in another planetransvers to said first-named plane, and a source of magnetic flux, saidmass and said source being so arranged that the mass forms a part of themagnetic circuit of the source.

5. A magnetic separator comprising a container, connections for passinga fluid bearing magnetic particles through said container, an isotropicmass of like, discrete, sharp-edged, imperforate magnetizable bodies inrandom orientations in said container, each of said bodies being ofconfiguration such that a part of said body'including an edge isdisposed in a plane transverse to another part of said body including anedge, and a source of magnetic flux, said mass and said source being soarranged that the mass forms a part of the magnetic circuit of thesource.

6. A magnetic separator comprising a liquidtight casing of magnetizablematerial, an annular axially magnetized magnet within said casing, onepole-face of said magnet being in contact with an intermal face of saidcasing, said casing providing a low-reluctance path for the flux of saidmagnet and being so disposed as to leave an an-- nular airgap space inthe magnetic circuit, a mass of like discrete magnetizable bodies insaid annular space, and connections to said casing for passing a fluidbearing magnetic particles radially through said mass.

7. A magnetic separator comprising a liquidtight casing of magnetizablematerial, an axially magnetized annular magnet within said casing, onepole face of said magnet being in contact with an internal face of saidcasing, said casing providing a low reluctance path for the flux of saidmagnet and being so disposed as to leave an annular gap in the magneticcircuit, a removable annular cartridge substantially filled with a massof like, discrete magnetizable attractor elements occupying said gap,the faces of said cartridge transverse to its axis being of lowreluctance for conducting the flux of said magnet axially through saidmass, the walls of said cartridge parallel to its axis being permeableto liquid and of relatively high magnetic reluctance, and means forpassing a liquid bearing magnetic particles through said permeable facesand radially through said mass.

8. A magnetic separator comprising a liquidtight casing of magnetizablematerial formed with an inlet and an outlet, an annular permanent magnetwithin said casing, one pole of said magnet being in contact with aninternal face of said casing, said casing providing a low reluctancepath for the flux so disposed as to leave an annular gapin the magneticcircuit, means for supporting a plurality of removable magnetizable,attractor elements in said gap, a duct within said casing leading fromsaid inlet to one side of the said annular gap, and a second duct withinsaid casing leading from the other side of said annular gap to said 71kof said magnet and being outlet, said ducts being arranged to conveyliquid bearing magnetizable particles through said gap in contact withsaid attractor elements.

9. A magnetic separator comprising a liquidtight casing of magnetizablematerial formed with inlet and outlet passages adjacent one end thereof,an annular permanent magnet within said casing adjacent said end, onepole of said magnet being in contact with an internal face of saidcasing, said casing providing a low reluctance path for the fiux of saidmagnet and being so disposed as to leave an annular gap in said magneticcircuit, means for supporting a plurality of magnetizable attractorelements within said gap, a duct within said casing disposed axiallythrough said annular magnet and communicating with one of said passages,and a sec-.- ond duct within said casing communicating with the other ofsaid passages, said ducts leading, respectively, to opposite sides ofsaid annular gap for conveying a liquid bearing magnetizable particlesthrough said gap in contact with said attractor elements.

10. A magnetic separator comprising a liquidtight casing of magnetizablematerial formed with an inlet and an outlet, an annular permanent magnetwithin said casing, one pole of said magnet being in contact with aninternal face of said casing, said casing providing a low reluctancepath for the flux of saidmagnet and being so disposed as to leave anannular gap in the magnetic circuit, means for supportin a. plurality ofremovable magnetizable attractor elements in said gap, a duct withinsaid casing leading from said inlet to one side of the said annular gap,and a second duct within said casing leading from the other side of saidannular gap to said outlet, said ducts being arranged to convey a liquidbearing magnetizable particles through said gap in contact with saidattractor elements, said casing being made in separable parts, one parthaving said inlet and outlet connections and another part comprising awall transverse to the axis of said annular magnet and removable fromsaid first-mentioned part, said removable wall section being of adiameter greater than said annular gap to permit the removal of saidattractor elements without disturbing said inlet and outlet connections.

11. A magnetic separator comprising a casing of magnetizable materialformed with an inlet and an outlet, an axially magnetized annular permanent magnet within said casing, one pole of said magnet beingsubstantially in contact with an internal face of said casing, saidcasing providing a low reluctance path for the flux of said magnet andbeing so disposed-as to leave an annular gap in the magnetic circuit,magnetizable attractor elements in said can, the magnetic flux throughsaid magnet, gap and attractor elements being substantially parallel tothe axis of said magnet, and means for conductin a liquid bearingmagnetizable particles from said inlet through said gap and past saidattractor elements to and through said outlet.

WILLIAM BYRD, JR.

e REFERENCES CITED Thefollowing references are of record in the fi1e ofthis patent:

UNITED STATES PATENTS Number Name Date 1,683,780 Hulsmeyer Sept, 11,1928 2,074,085 Frantz Mar. 16; 1937 1,677,804 Thayer July 17, 19282,037,316 Fenske Apr. 14, 1936 2,072,382 Robinson Mar. 2, 1937 2,149,764Frei Mar. 7, 1939 1,425,366

Chapman Aug. 8, 1922 Disclaimer 2,430,157.William Byrd, J1'., Princeton,N. J. MAGNETIC Smrnzg'non won RE- MOVING FINELY DIVIDED MAgNm'rlcMATERIAL FROM LIQUIDS. Patent dated Nov. 4, 1947. Disclalmer filed Apr.24, '1950, by the eesignee,

Samuel G. Frantz. Hereb enters this disclaimer to claims 8 to 11,inclusive, of said patent.

[ flicial Gazette May 16, 1950.]

